SCIENCE FILE

Dinosaur had a mouth like a vacuum cleaner

Chicago researchers have identified the fossil of a 110- million-year-old dinosaur with a mouth like the business end of a Hoover vacuum cleaner to feed its voracious appetite for grass, ferns and other low-lying greenery.

The wide, flat mouth of the Nigersaurus taqueti was lined with as many as 500 tiny, sharp teeth that enabled the animal to trim large areas of vegetation like a power lawn mower, paleontologist Paul Sereno of the University of Chicago said at a Thursday news conference sponsored by the National Geographic Society.

A CT scan of the fossil skull showed as many as eight replacement teeth stacked up behind each cutting tooth. With the stacking, worn-out teeth could be regularly replaced, Sereno said. "Among dinosaurs, Nigersaurus sets the Guinness record for tooth replacement," he said.

The dinosaur was a member of the sauropod family of plant-eating dinosaurs and was a younger cousin of the more familiar North American dinosaur Diplodocus. At 30 feet in length, Nigersaurus was relatively small for a sauropod, and its skull was unusually thin and light -- so much so that it was virtually translucent.

Its elongated neck was also thin and fragile, he said, suggesting that it was highly adapted for eating plants at ground level and not for plucking leaves from trees. Sereno called them the "cows of the Mesozoic" era.

The first bones from Nigersaurus taqueti -- named after the country where they were found and paleontologist Philippe Taquet -- were discovered by the French in the 1950s. Sereno named the species in 1999, shortly after his team recovered the skull. But, he said, it was not until they recently performed CT scans that they fully appreciated what they had found.

The report will be published Wednesday in the online journal PLoS One and described in the December issue of National Geographic magazine.